National study to shed light on aging

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McGill medical professor Christina Wolfson is one of the principal investigators for the Canadian Longitudinal Study on Aging, a long-term research project involving 50,000 participants from across the country (Photo: Owen Egan)

Imagine getting a phone call asking if you’d like to take part in a study … for the next 20 years.

It’s a pitch that makes telemarketing look like child’s play.

So no wonder Christina Wolfson, BSc’76, MSc’78, PhD’85, a professor in the Faculty of Medicine, says that the recruitment of research participants was probably the most stressful step in the Canadian Longitudinal Study on Aging (CLSA). After all, it meant rounding up 50,000 people across Canada from 45 to 85 years old.

Now well underway — and its initial data already the focus of follow-up research projects – CLSA is the largest study of its kind ever undertaken in Canada. It aims to find ways to help people “live long and live well,” and gain insight into why some fare better than others in the aging process.

“There have been smaller studies that have mainly recruited older people,” says Wolfson, a professor of medicine, epidemiology, biostatistics and occupational health, and one of three principal investigators for the national study.

“We started recruitment at age 45 because we’re looking at aging not the aged,” adds Wolfson.

“We want to look at the baby boomers moving into the older ages and also aging amongst the older people.”

The study is nearing the end of the second wave of data collection from its 50,000 participants and will begin a third wave in late spring. Of the study cohort, 20,000 are tracked through telephone interviews, while 30,000 are interviewed at home and then followed at 11 data collection sites across Canada.

The Montreal site at the Research Institute of the McGill University Health Centre sees 3,000 study participants every three years. Interviewers first visit them in their homes asking questions about everything from their work life to memory and mobility, loneliness and diet.

Then participants go to the downtown Montreal site for physical assessments and more interviews. Those tests include an electrocardiogram, a vision test that also looks for macular degeneration, and neuropsychological testing. Staff collect blood and urine samples, if participants agree, and most do.

Côté, who worked in education and then volunteered for a Quebec association of retired public-sector workers, said he was interested in taking part when called about the study.

While he might not benefit from the study himself, Côté suggests his involvement might help those who follow him. “I had no problem to offer time for that study.”

“We’re collecting research data that’s going to be used for research, so [participants] get very little out of it. So it really is altruism,” says Wolfson, whose own mother was randomly recruited for the telephone cohort.

The longitudinal study is a “research platform” meant to be mined by researchers who have to apply to use the anonymous data/biological samples.

To date, 114 research projects have received the green light to access the data. Among the varied topics being studied are giving up driving, frailty and dementia. One of Wolfson’s studies focuses on the physical and mental health of older veterans. (The CLSA data indicates 4,000 self-reported veterans are part of the cohort.)

She anticipates a lot of material will emerge in the next year from the longitudinal study because researchers will have analyzed the baseline data and start submitting their papers for publication.

The CLSA plans to release its own descriptive report this spring about the baseline data to draw researchers attention to it. “Obviously the success of this whole initiative is if other researchers use the data,” Wolfson says.

They’ll be able to talk about the prevalence of various conditions in the report, she says, including an estimate for Parkinson’s disease.

“We’ll also be able to estimate the incidence of Parkinson’s disease – so the number of new cases over time, which we really don’t have data on at the national level in Canada,” Wolfson says.

They can also look at the pattern of body mass index by age, sex and province. The study’s sample size is large enough to be representative of the Canadian population.

The challenge now is retention, says Wolfson, who notes it was higher than anticipated for the first follow-up. They are trying to find ways to keep people in the study who want to stick with it but can’t because they’re hard of hearing, for instance. They’re also developing strategies to follow people if they become institutionalised or cognitively impaired.

Mounting the large-scale study was years in the making long before recruitment began in 2009. The Canadian Institutes of Health Research initiated the idea in 2001 and granted funding the next year to Parminder Raina from McMaster University, who is the lead principal investigator, Wolfson, and co-principal investigator Susan Kirkland from Dalhousie University, to develop a proposal for the study.

“It’s been a long haul,” says Wolfson. “It’s been an interesting journey.”